Abscess of Liver

DEFINITION:

Two types of liver abscess; Areas affected by either: Right lobe only (65%), Both lobes (30%), Left lobe only (5%)
- Pyogenic, usually arise from intraabdominal infections
- Amebic, usually arise from colonic infections with invasive Entamoeba histolytica

EPIDEMIOLOGY:

ETIOLOGIES:

Pyogenic: Majority of causes unknown (Cryptogenic)
- Biliary tract diseases are the most common known source (35% of cases); Most cases result from cholangitis or acute cholecystitis
- Another 30% of cases caused by: Diverticulitis, Crohn’s, Ulcerative Colitis, Bowel perforation
- Another 15% occur via direct extension from a contiguous source, such as subphrenic abscess or empyema of the gallbladder
- Intraabdominal infections with bacterial seeding via portal vein can occur, i.e. dental disease, endocarditis
- Other causes: Malignancy of pancreas, common bile duct, ampulla; Endoscopic and surgical intervention of the biliary tree
Amebic:
- Bile is lethal to amebas, thus infections of gallbladder and bile ducts do not occur

PATHOPHYSIOLOGY:

Pyogenic
- Organisms: gram(−) organisms 50-70% of cases (E. coli), gram(+) 25% of cases, Anaerobes 50% of cases
- Abscesses from biliary origin tend to be multiple and small size, involving both lobes of the liver
- Septic emboli via portal vein tend to be solitary; Contiguous sources tend to be solitary
Amebic:
- Usually arise from colonic infections with invasive Entamoeba histolytica
- Tend to be solitary and large, most common in right lobe